Method and apparatus for reducing power needed for compression



July 2 1957' w. L. MORRISON 2,799,997

METHOD AND APPARATUS FOR REDUCING POWER NEEDED FOR COMPRESSION FiledSept. 9, 1954 INVENTOR, Willard L. Morrison y Parker 8: Carter ATTORNEYSUnited States atent METHOD AND APPARATUS FOR REDUCING PQWER NEEDED FORCGMPRESSION Willard L. Morrison, Lake Forest, Ill., assignor, by directand mesne assignments, to Constock Liquid Methane Corporation, acorporation of Delaware Application September 9, 1954, Serial No.455,652

4 Claims. (Cl. 62-1) This invention relates to processes involving thecompression of various gaseous materials and has for one object toprovide a method for reducing the power necessary to compress saidgaseous materials.

Another object is to provide an apparatus-eifective to reduce the powernecessary to compress gaseous materials.

Another object is to provide a method of cooling gaseous materials whichare to be compressed prior to such compressin in order to reduce thepower necessary to compress said gaseous materials to a desiredpressure.

Another object is to provide a method of cooling gaseous materials priorto their compression in order to reduce the power necessary for suchcompression wherein the cooling medium may be utilized, also to producethe power required for such compression.

Other objects will appear from time to time in the course of thespecification and claims.

The invention is illustrated more or less diagrammatically in theaccompanying drawing wherein the single figure comprising the drawing isa top plan view in cross section.

Like parts are indicated by like characters throughout the specificationand drawings.

Referring to the drawing, 1 is a barge or similar carrier which may betied up at a dock or similarly located alongside a plant wherein gaseousmaterials are processed, the process involving at one or more stages thecompression of such gaseous materials. The carrier 1 may have one ormore containers or tanks such as that illustrated at 2. Any suitablepumping means such as the pump generally shown at 3 may be employed totransfer a supply of liquefied natural gas from the containers 2, forexample, through the piping or conduit 4 to a reservoir 5. Similarly apumping means 6 may be employed to transfer the liquefied natural gasfrom the reservoir through pipe 7. A coil 8 may be connected to the pipe7 as indicated at 9 and may be enclosed within a heat exchange chamber10. A conduit 11 may be employed to convey the gaseous materials whichare to be compressed, to the chamber 10, for heat exchange contact withcoil 8. A conduit 12 is connected to the heat exchange chamber to conveythe gaseous material which have been cooled therein from the chamber 10to a compressor mechanism 13. The coil 8 has an outlet pipe 14 leadingfrom the chamber it A branch conduit 15 is connected at one end to thepipe 14 and at its opposite end to an internal combustion engine whichis powered by gas vaporized and warmed by heat exchange in coil 8,illustrated diagrammatically at 16.

It will be realized that the pipe 11 is connected to a source of supplyof gaseous materials and that the pipe 14 may be connected to a varietyof mechanisms and may in fact be so connected as to direct the naturalgas which has been vaporized by heat exchange in the chamber 10 to apoint of use in the process of the plant in which the gaseous materialsare treated. Since the elements to which the pipes 11 and 14 may beconnected do not form any ice part of the present invention they are notillustrated or further discussed herein.

An outlet conduit 20 leads from the compressor 13 and conducts thegaseous materials compressed therein to a second heat exchange chamber21. A water pump 22 is effective to direct water under pressure througha water pipe 23. A coil 24 is positioned within the heat exchangechamber 21 and is connected, at one end to the branch conduit 25 leadingfrom pipe 23 and at its opposite end to a water discharge pipe 26extending from the chamber 21. An outlet pipe 27 is connected to thechamber 21 to conduct the gaseous materials which have been cooledwithin the chamber 21 by the water passing through the coil 24, to athird heat exchange chamber 28 which contains the coil 29. The coil 29is connected at one end to the liquid natural gas supply pipe 7 and atits opposite end to an outlet conduit 30. An outlet pipe 31 is connectedto the chamber 28 to convey the gas cooled therein by the liquid naturalgas flowing through the coil 29 to a second compressor 35. A branchconduit 36 is connected to the pipe 30 to convey the natural gasvaporized and warmed by heat exchange, to an internal combustion engineillustrated at 37. The pipe 30 may be connected to a suitable mechanismas described above with relation to pipe 14.

40 is a discharge conduit leading from compressor 35 to conduct thegaseous materials compressed therein to a fourth heat exchange chamber41 through which extends the coil 42 which is connected at one end tothe water supply pipe 23 and at its opposite end to the water dischargepipe 43. 45 is an outlet conduit connected to the chamber 41 to conveythe gaseous materials cooled therein by heat exchange with the waterpassing through the coil 42. The outlet pipe 45 may be connected to avariety of mechanisms employed in the processing plant or, if desired,it may be connected to a fifth heat exchange chamber similar to thechamber 28. It will be realized that the mechanism illustrateddiagrammatically at 8-20 may be repeated at any desired number of pointswithout departing from the nature and scope of the invention.

59 illustrates fiy-wheels employed with the compressors 13, 35.

The use and operation of this invention are as follows:

A method is provided for reducing the power necessary to compressgaseous materials which involves the concept of cooling the gases priorto such compression by the use of liquefied natural gas as a refrigerantpassed in heat exchange relationship with such gaseous materialsimmediately prior to compression thereof.

The liquefied methane which is supplied in tonnage quantities at atemperature of -258 F. within the containers 2 and reservoir 5 is pumpedthrough the heat exchange coil 8. The gaseous materials entering theheat exchange chamber 10 are thus cooled as they pass about the coil 8and the liquefied natural gas is vaporized. The cooled gaseous materialsare conveyed from the chamber 10 to a compressor 13 by the conduit 12. Aportion of the vaporized natural gas flowing from the coil 8 through thepipe 14 is bled off and directed into the internal combustion engine 16where it serves as a fuel to provide the power necessary to operate thecompressor 13. Thus, by liquefying natural gas and supplying it inquantity, the refrigerant eifect is utilized to cool gaseous materialsabout to be compressed and to use also at least a portion of the naturalgas in gaseous phase resulting from such cooling as a fuel to providethe necessary compression power.

As natural gas is often used as one of the raw materials in certainprocessing plants and since only a portion of the natural gas vaporizedin the chamber 11 is necessary to provide the amount of power needed forcompressing the gaseousmateria1s which. have been cooled within thechamber 10,. the. remaining vaporized natural gas. may

be used as raw material in the process within the plant,

or may be diverted to other use in or out of the plant.

1 The gaseous materials: compressed by the compressor 13 flow outwardtherefrom through the outlet 'c'onduitiZti,"

havingbeenraisedin tmperaturebycompression. Under certain Circumstancesit may b e'foundadvisableto produce water cooled heat exchanger throughthe conduit 27 maybe "directed into the compressing plant or may beagain cooled by means corresponding to those already described. I 7

It will beunderstood that the compressor outlet 20 could be, undercertain circumstances, connected directlyto the heat exchange chamber 28wherein the gases which were heated to some extent by the [compressor 13would be again cooled beforeentering a. second compressor 35.

It isknown that the horsepower required to compress gases per unit massvaries directly as the inlet absolute temperature from the same initialpressure to the same final pressure. While various means have beenemployed to cool. said gases prior to compression, I have found thatnatural gas liquefied at about -258 F. may be utilized efiectively tocool said gases prior to compression and this use of natural gas isproductive of particularly advantageous results in that the natural gas,when supplied .in large quantities in liquefied form at or about --258F..may be utilized first, as an effective coolant for gaseous materialsin a processing plant, then as a fuel to power the compressionmechanism, and thirdly, as a raw material usable in the process withinthe plant. Also any surplus of natural gas in gaseous phase resultingfrom the use of liquefied natural gas as a coolant may be utilized as afuel toeconomically and effectively power other mechanisms within theplant.

While .I have illustrated my invention as using the gas as fuel ininternal combustion engines, it will be obvious that the gas might beused just as well as fuel for any other means of generating thenecessary power.

I have referred to the vaporization of the liquefied gas by heatexchange as it passes through the coils 8 and 29. Such gasification willtake place if the pressure in those coils issubstantially at atmosphericbecause liquefied methane or natural gas boils at approximately -258 P.On the other hand, if by control of the exhaust pressure through thepipes 14 and 3t) and by operation of the pump 6, the pressure in thecoils '8 and 29 is maintained above atmospheric, then the boiling pointof the liquefied methane. will be above --258 F.

I claim:

1. In the method of raising the temperature of a stream.

of methane from about minus 258 F. to substantially atmospherictemperature while simultaneously substantially compressing a stream of asecond gas, the steps which comprise: (a) in a first step passing thecold methane in heat exchange with the second gasto substantially reduceits temperature and. increase its density, (b) in a second stagecompressing the said second gas efiiuent from said first stage, (0) in athird stage water cooling the second gas efiluent from said secondstage, (d)' in a fourth stage passing a further stream of cold methanein heat exchange relation with said second gas efiluent' from said thirdstage, (e) in a fifth stage compressing the second. gas effluent fromsaid fourth stage, and (f) in a sixth stage water.

cooling to substantially atmospheric temperature the second gas effluentfrom said fifth stage.

2. The method of substantially raising the temperature of a stream of afirst gas from a temperature substantially below atmospherict'o'substantially atmospheric temperature while simultaneouslycompressing a second gas to a substantially elevated pressure whichcomprises in progressive stages compressing said second gas stream,passing the stream of said second gas entering each com-s pressor inheat exchange relation with separate portions of said first gas, andwater cooling the stream of said second gas as 'it leaves, each of saidcompressors, and subsequently utilizing said heated-up first gas as afuel. 7

3. The method of claim 1 characterized further in that a portion of themethane stream after heat exchange with 7 the combination of a pluralityof heat exchangers,rmeans to convey said second gas stream sequentiallythrough said' heat exchangers means of conveying difierent portionsrespectively of the stream of said first gas through said heatexchangers, means for compressing said second gas stream after it haspassed through one of saidheat exchangers and means for conveying waterin heat exchange relation with said stream of said second gas as itleaves at least one of said compressors.

References'Cited in the file of this patent UNITED STATES PATENTS CooperOct., 18,

